P0AE6: Precharge contactor control is low while enabled

P0AE6 is the hybrid/EV battery precharge contactor A control-circuit low code. GM's 2018 table describes a check of the precharge contactor high-side driver for a short-to-ground response when commanded on.

The circuit result and the precharge result differ

For this monitor, a voltage at or below 5.35 V meets the low criterion. The 12 V battery must be above 10.2 V. Thirteen failed samples out of 16 at 12.5 milliseconds per sample satisfy the listed evaluation; the reporting type is B, two trips.

Precharge is a system sequence, but P0AE6 specifically concerns its contactor control circuit. The code alone does not measure how quickly the high-voltage bus charged, determine the precharge resistance or prove the contactor contacts failed mechanically. Those are separate diagnostic questions.

Use the on command as the reference

A useful scan record links the low feedback to the on command and adequate low-voltage supply. Without that context, a low control value may be normal for another state. Companion precharge or power-bus codes can add evidence, but their presence does not change what this driver monitor actually measured.

After a repair, confirm the eligible control test and the vehicle's prescribed precharge checks. Do not bypass the precharge path to “see if it starts”; this source provides neither authorization nor a procedure for doing so. Contactor, pack and high-voltage bus work must use qualified service personnel and vehicle-specific instructions.

Source and applicability

This explanation follows the documented GM monitor, not a verified application to every vehicle with this code. Confirm the vehicle, reporting module and calibration in current service information. GM diagnostic table, physical page 780.